Attempts will be made to synthesize stereoisomeric forms of 3,4-dihydroxy-1,2-epoxy-7-methyl-1,2,3,4-tetrahydrobenz[a]anthracene, and 3,4-dihydroxy-1,2-epoxy-7,12-dimethylbenz[a]anthracene. Likewise, stereoisomeric forms of 9,10-dihydroxy-7,8-epoxy-7,8,9,10-tetrahydro-3-methylcholanthrene and of 9,10-dihydroxy-7-8-epoxy-7,8,9,10-tetrahydro-3,6-dimethylcholanthrene, will be synthesized. These oxygenated derivatives are hypothesized to be the carcinogenic metabolites of 7-methylbenz[a]anthracene, 7,12-dimethylbenz[a]anthracene, 3-methylcholanthrene, and 3,6-dimehtylcholanthrene, but none of the compounds, 1-4 is at present, available to research workers. These oxygenated compounds are needed to evaluate experimentally if the diolepoxide theory of carcinogenesis extends to the above polycyclic hydrocarbons. In addition the 1-,2-,3-, and 4-hydroxy derivatives of 7-methylbenz[a]anthracene as well as the 1,4-and 3,4-quinones of and the 7,10- and 9, 10-quinones of 3-methylcholanthrene, and of 3,6-dimethylcholanthrene, will be prepared. All the compounds prepared will be fully characterized structurally and stereochemically and will be made available to qualified biochemical collaborators.